Dynamics of Atmospheric Pressure Plasma Plumes in the Downstream and Upstream Regions

Abstract

A novel plasma jet driven by an alternating current voltage is developed to generate atmospheric pressure non-equilibrium plasma plumes in the downstream region and in the upstream one of the argon flow. The angle between the rod electrode and the gas flow can be changed easily, and the plume lengths in the downstream and upstream regions are investigated as a function of the angle and the peak voltage. With increasing the peak voltage, the discharge pulse number tends to increase for every half voltage cycle. Using an intensified charge-coupled device camera, the dynamics of the plasma plumes is also investigated in the downstream and upstream regions. The dynamics of the plumes is qualitatively explained by the streamer propagations influenced by residual charges.

Improved performance of a barrier-discharge plasma jet biased by a direct-current voltage

“…For the discharges with or without V b , the tungsten electrode of the coaxial DBD jet is the instantaneous anode. Therefore, the guided streamer is directed from the anode to the cathode, which is often called a cathode-directed streamer (or positive streamer) 16 32 . The propagation behavior of the positive streamer has been explained based on photo-ionization 29 32 .…”

“…From the view point of discharge dynamics, most of the plasma plumes are composed of fast-moving plasma bullets (guided streamers) 13 14 , which propagate along a predetermined path (the gas flow direction) 15 . Moreover, the propagation track of the guided streamer can be straight-line 16 , snakelike or helical 17 18 . An electric field perpendicular to the gas flow has also been used to change the propagation direction of the guided streamer 19 .…”

Comparison of two cold atmospheric pressure plasma jet configurations in argon

“…The appearance of several ionization waves during one half‐period of applied voltage has been observed at certain conditions both with Ar and He for both CAPJ configurations . In general, the ionization wave is initiated when the electric field becomes sufficiently high for the satisfaction of Meek criteria for streamer breakdown.…”

Effect of the angle between the electric field and the gas flow one on the plasma plume dynamics at atmospheric pressure

“…Walsh等人 [18] [15,[20][21][22] . 利用单针结构的射流, Wu等人 [15] 研究发现上游羽产生的电子、离子及亚稳态粒子可 以影响下游羽的传播 下的电离波传播 [14][15][16][17] , 即放电对应着流光过程 [23] .…”

“…基于碰撞辐射模型, 下游羽的电子激发温度(T e )可 以利用谱线强度比的方法测得 [24] [23] . 由于图6中T e 的空间分布间接反映出在传播过程 中净电场E(外加电场与内电场矢量和)先增加后减小, 并且E的分布与子弹(流光)的传播速度分布一致(图5).…”